1. Field of the Invention
This invention relates to prosthetic heart valves and more particularly to a device for holding and positioning the heart valve during surgical implantation.
2. Description of Prior Art
Natural heart valves taken from animals, particularly porcine heart valves, have been widely used for several years in the replacement of diseased valves in humans. The porcine valve suitably treated with gluteraldehyde or other fixative solution is mounted on a cloth covered stent or supporting framework prior to implantation. The stent is typically an open cylindrical device having a gently scalloped base curve and three axially extending commissure support struts adapted to support the margins of the valve cusps as illustrated in U.S. Pat. No. 3,570,014. The stent is constructed of metal or plastic, covered with a cloth material, and provided with a circumferential sewing cushion extending outward from the base.
To facilitate handling of the valve during implantation, valve manufacturers have provided various valve holding devices which attach to the valve and allow the surgeon to more easily place the mounting sutures and position the valve in the original valve annulus. Once the valve and sutures are in position, the valve holder is detached from the valve and the surgical implantation procedure is completed.
Valve holders of the prior art consist in general of a support member sutured to the sewing cushion of the valve and an elongated handle which attaches to the support member by screw threads or other suitable means. The valve holder is separated from the valve by cutting the attaching sutures and withdrawing the handle and support member from the operating area. The handle may optionally include an elbow or other means to permit the valve to be angled relative to the main axis of the handle.
In mitral and tricuspid valve replacement, the prosthetic valve is inserted into position with the cusps directed away from the surgeon. In this position the cusps of the valve are subject to damage from snagging in the surrounding anatomical profile as the valve is moved into position and difficulty is sometimes encountered in inserting the valve into the original valve annulus. The mounting sutures are also suseptible to looping over the commissure posts as the valve is moved into position. Even with the aid of a valve holder, placing the valve in position is a sensitive and delicate procedure.
It is accordingly an object of the present invention to provide a valve holder for natural tissue prosthetic heart valves. It is a further object of this invention to provide a holder for mitral and tricuspid valves which facilitates the positioning of the valve within the original valve annulus. It is a yet further object of the present invention to provide a valve holder which permits the commissure support struts of the valve stent to be drawn toward one another prior to placement of the valve, thereby reducing the diameter of the leading portion of the valve and the possibility of snagging the valve cusps and damaging the delicate valve tissue. These and other objects of the invention will be apparent from the ensuing description and claims.